The present invention was developed in order to simplify the task of drilling holes to a pre-determined depth. Drill bits are widely used in the construction, carpentry, woodworking, metal working trades and the like. Drilling, in particular, is a common operation for forming a cylindrical hole with a straight -fluted or twist drill.
Machines used in drilling include manually operated and power drills, as well as various types of drilling machines such as a bench drill press, an upright drill press, and a radial drill press. In all of these drilling machines, a drill bit is used to drill the hole, and many times, these holes are drilled only to a specific depth.
For wood drilling, in particular, it is often necessary to drill only to a specific depth. For example, the installation of a door hinge and the like, where it is not wanted to drill all the way through. Furthermore, it is desired to drill to a sufficient depth for the screws to be set for purposes of strength of setting the screw.
Various drill stops and drill stop collars have been developed to limit the depth the drill bit enters the wood, or the material to be drilled. However, the drill stops previously developed do not always give the desired precision depth of drill and in most cases complicated to use and are not easy to manufacture or to use at either a job site, a shop or at home. It has also been very difficult to measure and mark the depth on a round drill bit. The following is a list of related patents, however none of the cited patents disclose or even suggest the device of the present invention, a tubular housing, a precision turn screw depth setting shaft, and a set screw collar.
U.S. Pat. No. 4,813,822, issued to Biek on Mar. 21, 1989 PA0 U S. Pat. No. 4,961,674, issued to Wang et al on Oct. 9, 1990 PA0 U.S. Pat. No. 5,078,552, issued to Albel on Jan. 7, 1992 PA0 U.S. Pat. No. 5,147,164, issued to Fraver on Sept. 15, 1992